Reply
 
Thread Tools Display Modes
  #1   Report Post  
Posted to rec.audio.tech
Im_Beta_00 Im_Beta_00 is offline
external usenet poster
 
Posts: 3
Default Condenser microphones and water?

The following message was displayed prominently on the exterior of the box to
the Gold Edition MXL V67G microphone I bought:

CAUTION

All condenser microphones are very sensitive to moisture.
For close vocal use, MXL strongly recommends the use of a
pop filter or foam wind screen to prevent permanent damage
to the transducer.

which makes me wonder if condenser microphones have a limited lifespan in
general, just from the humidity in the air. Is this something I should worry
about? If it is, what can I do about it? I have heard of some people
protecting their microphones by sticking them in rubber balloons.

I don't live in a sunny state, I live in Portland, Oregon, and the summer is
over, and we are proceeding into our rainy season.
  #2   Report Post  
Posted to rec.audio.tech
Richard Crowley Richard Crowley is offline
external usenet poster
 
Posts: 4,172
Default Condenser microphones and water?

Im_Beta_00 wrote:
The following message was displayed prominently on the exterior of
the box to the Gold Edition MXL V67G microphone I bought:

CAUTION

All condenser microphones are very sensitive to moisture.
For close vocal use, MXL strongly recommends the use of a
pop filter or foam wind screen to prevent permanent damage
to the transducer.

which makes me wonder if condenser microphones have a limited
lifespan in general, just from the humidity in the air. Is this
something I should worry about? If it is, what can I do about it? I
have heard of some people protecting their microphones by sticking
them in rubber balloons.

I don't live in a sunny state, I live in Portland, Oregon, and the
summer is over, and we are proceeding into our rainy season.


Moisture of any kind, and particularly "conductive" moisture like
breath condensation will short out the ultra-high impedance of the
condenser capsule and wiring. Even partial shorting of this high-
impedance node will cause significant noise and loss of signal.
That is the primary vulnerability of condenser mics to moisture.

Unless the water leaves conductive residue behind, once the
moisture is gone, no permanent damage remains. However a
secondary mode of long-term deterioration is leaving the surfaces
sticky and more prone to collecting and holding dust, etc. from
the air. This may be the "permanent damage" MXL is referring
to. It can be cleaned, but it is a delicate operation best done
by skilled and experienced technicians, and so maybe beyond
the cost/benefit of fixing a low-cost microphone.

I also live in the Portland metro area (Hillsboro) and I am not
concerned about ambient humidity harming any of my many
condenser microphones.



  #3   Report Post  
Posted to rec.audio.tech
Im_Beta_00 Im_Beta_00 is offline
external usenet poster
 
Posts: 3
Default Condenser microphones and water?

Richard Crowley wrote:
Im_Beta_00 wrote:


snip

which makes me wonder if condenser microphones have a limited
lifespan in general, just from the humidity in the air. Is this
something I should worry about? If it is, what can I do about it? I
have heard of some people protecting their microphones by sticking
them in rubber balloons.

I don't live in a sunny state, I live in Portland, Oregon, and the
summer is over, and we are proceeding into our rainy season.


Moisture of any kind, and particularly "conductive" moisture like
breath condensation will short out the ultra-high impedance of the
condenser capsule and wiring. Even partial shorting of this high-
impedance node will cause significant noise and loss of signal.
That is the primary vulnerability of condenser mics to moisture.

Unless the water leaves conductive residue behind, once the
moisture is gone, no permanent damage remains. However a
secondary mode of long-term deterioration is leaving the surfaces
sticky and more prone to collecting and holding dust, etc. from
the air. This may be the "permanent damage" MXL is referring
to. It can be cleaned, but it is a delicate operation best done
by skilled and experienced technicians, and so maybe beyond
the cost/benefit of fixing a low-cost microphone.

I also live in the Portland metro area (Hillsboro) and I am not
concerned about ambient humidity harming any of my many
condenser microphones.


Hate to confess it, but I am a teensy bit hard of hearing. Is there any
software that will let me 'see' what the difference is, between a new
microphone, and one that has been compromised? I mean, compromised from the
accumulation of grease and dirt after the water has evaporated. Not only
that, but I was wondering about the possibility of those little metal ribbons
inside condenser microphones. Do they ever corrode?

Which software do you suggest for generating a sound spectrograph?

My setup, is an unexpanded Mac mini, and the aforementioned MXL V67G
microphone. It may seem a little old-fashioned, but I was thinking of using a
tuning fork at about a foot's distance, and set my Fostex FR-2LE's gain more
or less to the middle. Would that work?
  #4   Report Post  
Posted to rec.audio.tech
Richard Crowley Richard Crowley is offline
external usenet poster
 
Posts: 4,172
Default Condenser microphones and water?

Im_Beta_00 wrote:
Hate to confess it, but I am a teensy bit hard of hearing. Is there
any software that will let me 'see' what the difference is, between a
new microphone, and one that has been compromised? I mean,
compromised from the accumulation of grease and dirt after the water
has evaporated.


If the noise or distortion is audible and detracts from the signal
you are recording, then it is compromised.

Not only that, but I was wondering about the
possibility of those little metal ribbons inside condenser
microphones. Do they ever corrode?


Little metal ribbons inside condenser microphones?
I don't know what you mean.

Condenser microphones typically have a round diaphragm
of stretched plastic. The diaphragm has been made conductive
by some method such as metal evaporation or sputtering, etc.
Very early models (mid 20th century) used kinds of plastic
that weren't long-term stable, but modern mics have life
expectancy of many decades, minimum.

Failure modes include any kind of mechanical trauma,
or the diaphragm picking up mass from debris stuck to
it (and causing it to lose sensitivity), or dirt and/or
moisture causing shorting or leakage of the very high
impedance node.

Dynamic microphones usually have stamped or molded
plastic diaphragms onto which the wire coil is glued, etc.
In addition to physical trauma, dynamic mics sometimes
collect ferrous (magnetic) metal bits which are attracted
and held by the strong magnetic field.

The only kinds of mics that have "little metal ribbons" are
ribbon mics which have a very thin ribbon of aluminum
suspended inside a strong magnetic field. In addition to
attracting and holding metal debris, ribbon mics have a
failure mode of the ribbon stretching and/or breaking
from strong wind or dropping, etc.

Which software do you suggest for generating a sound spectrograph?

My setup, is an unexpanded Mac mini, and the aforementioned MXL V67G
microphone. It may seem a little old-fashioned, but I was thinking
of using a tuning fork at about a foot's distance, and set my Fostex
FR-2LE's gain more or less to the middle. Would that work?


What software are you using? Does it make a specgtrograph?
Once you have your spectrograph, how do you know if it is
good or bad?

I would start by characterizing the audio chain. First the
A/D converter, then the mic preamp and cable, and
finally the microphone itself. How much noise is there
and what does it sound and look like?

If you know how much noise you are getting without the
mic plugged in, then you know how much the microphone
is contributing. If you are testing for noise, you need the
quietest place you can find. You could try waiting until
3am and burrying the mic in a big pile of bedding and
pillows, etc.

Conider that you may be obsessing about something that
probably doesn't make the top 100 things to worry about.


  #5   Report Post  
Posted to rec.audio.tech
Peter Larsen[_3_] Peter Larsen[_3_] is offline
external usenet poster
 
Posts: 2,295
Default Condenser microphones and water?

Im_Beta_00 wrote:

The following message was displayed prominently on the exterior of
the box to the Gold Edition MXL V67G microphone I bought:


CAUTION


All condenser microphones are very sensitive to moisture.
For close vocal use, MXL strongly recommends the use of a
pop filter or foam wind screen to prevent permanent damage
to the transducer.


Common sense.

which makes me wonder if condenser microphones have a limited
lifespan in general, just from the humidity in the air.


No.

Is this something I should worry about?


No.

If it is, what can I do about it?


At the price point of the mic in question use it for target practice.

I have heard of some people protecting their microphones by sticking
them in rubber balloons.


You have overlooked one word frequently found in humidity specs "non
condensing", ie. water droplets may not be allowed to form on the object.
That would just keep condensation moisture contained. A cloth bag or a paper
envelope does a a great job of keeping particle contamination away from a
mic that is left on a micstand permanently in studio, I recall some fairly
long thread about which mediocre whisky that comes in the best bag for the
purpose of storing a mic.

I don't live in a sunny state, I live in Portland, Oregon, and the
summer is over, and we are proceeding into our rainy season.


Put the mic on phantom power a day before you will use it, that is what I
do. If you are a studio then build a mic cupboard with connectors that
supply phantom power and keep the mics powered up permanently while stored.

To evaluate a microphone or compare microphones: record speech, it is an
excellent test signal.

To evaluate in a year .... guess what ...

To evaluate in 10 years .... guess what ...

Kind regards

Peter Larsen





  #6   Report Post  
Posted to rec.audio.tech
Im_Beta_00 Im_Beta_00 is offline
external usenet poster
 
Posts: 3
Default Condenser microphones and water?

Peter Larsen wrote:
Im_Beta_00 wrote:


snip

which makes me wonder if condenser microphones have a limited
lifespan in general, just from the humidity in the air.


No.

Is this something I should worry about?


No.

If it is, what can I do about it?


At the price point of the mic in question use it for target practice.


Um, okay.

I have heard of some people protecting their microphones by sticking
them in rubber balloons.


You have overlooked one word frequently found in humidity specs "non
condensing", ie. water droplets may not be allowed to form on the object.
That would just keep condensation moisture contained. A cloth bag or a paper
envelope does a a great job of keeping particle contamination away from a
mic that is left on a micstand permanently in studio, I recall some fairly
long thread about which mediocre whisky that comes in the best bag for the
purpose of storing a mic.


Hmmm. Is that because high proof whiskey yields alcoholic vapors that don't
harm the microphone?

I don't live in a sunny state, I live in Portland, Oregon, and the
summer is over, and we are proceeding into our rainy season.


Put the mic on phantom power a day before you will use it, that is what I
do. If you are a studio then build a mic cupboard with connectors that
supply phantom power and keep the mics powered up permanently while stored.


That would warm up the microphone, and make the moisture evaporate?

To evaluate a microphone or compare microphones: record speech, it is an
excellent test signal.


Well, I am not yet deaf as a stone, but I think a sound spectrograph would be
better.

To evaluate in a year .... guess what ...

To evaluate in 10 years .... guess what ...

Kind regards

Peter Larsen


Thanks.
  #7   Report Post  
Posted to rec.audio.tech
Peter Larsen[_3_] Peter Larsen[_3_] is offline
external usenet poster
 
Posts: 2,295
Default Condenser microphones and water?

Im_Beta_00 wrote:

in studio, I recall some fairly long thread about which mediocre
whisky that comes in the best bag for the purpose of storing a mic.


Hmmm. Is that because high proof whiskey yields alcoholic vapors
that don't harm the microphone?


No, because the cloth bag the cheap whisky body is sold in looks great in a
studio.

Put the mic on phantom power a day before you will use it, that is
what I do. If you are a studio then build a mic cupboard with
connectors that supply phantom power and keep the mics powered up
permanently while stored.


That would warm up the microphone, and make the moisture evaporate?


Erm ... climate here in Copenhagen is not dissimilar from where you are. I
don't think there is a problem with condensing moisture that matters inside
a warmed up building. I suggest it because I often notice on location that
microphones tend to open up sonically after having been powered up for more
than one hour. It may be less wise to keep a valve type microphone powered
up constantly, also from a CO2 point of view, those I have come with a high
voltage power supply.

To evaluate a microphone or compare microphones: record speech, it
is an excellent test signal.


Well, I am not yet deaf as a stone, but I think a sound spectrograph
would be better.


Surprise surprise, it can tell you how a microphone measures, but not how it
sounds and not how the measurement correlates with the percieved sound of
the mic. It is the same problem as with loudspeakers ... one factor is
directivity and the other is delayed resonance, ie. a resonance that causes
only minor - if any - change of measured frequency response but - by sound
in that range decaying slower than the rest of the audio range - generates a
noticeable colouration of the sound.

A spectogram can tell you, if you have a repeatable sound source, whether
the mic has changed. To evaluate a microphones sound speech and a the rattle
bundle of keys has excellent mileage - as has a piano quartett using a full
size concert grand.

Thanks


In the real world of recording microphone positioning matters more than
minor sonic variations between microphones, the mileage of an inch of
movement of a pair used for an ensemble can be surprising if that inch of
movement takes your mic away from a "bad" reflection from the ceiling. Worry
less, record more, learn, enjoy!

Kind regards

Peter Larsen


  #8   Report Post  
Posted to rec.audio.tech
news reader news reader is offline
external usenet poster
 
Posts: 7
Default Condenser microphones and water?

I recall some fairly
long thread about which mediocre whisky that comes in the best bag for
the
purpose of storing a mic.


Hmmm. Is that because high proof whiskey yields alcoholic vapors that
don't
harm the microphone?


Or because whiskey is good for drinking and aids in creativity?


  #9   Report Post  
Posted to rec.audio.tech
Im_Beta_00[_2_] Im_Beta_00[_2_] is offline
external usenet poster
 
Posts: 5
Default Condenser microphones and water?

Peter Larsen wrote:
Im_Beta_00 wrote:
Well, I am not yet deaf as a stone, but I think a sound spectrograph

would be better.


Surprise surprise, it can tell you how a microphone measures, but not how it
sounds


I think that's exactly what it /does/ measure.

and not how the measurement correlates with the percieved sound of
the mic. It is the same problem as with loudspeakers ... one factor is
directivity and the other is delayed resonance, ie. a resonance that causes
only minor - if any - change of measured frequency response but - by sound
in that range decaying slower than the rest of the audio range - generates a
noticeable colouration of the sound.

A spectogram can tell you, if you have a repeatable sound source, whether
the mic has changed. To evaluate a microphones sound speech and a the rattle
bundle of keys has excellent mileage - as has a piano quartett using a full
size concert grand.

Thanks


In the real world of recording microphone positioning matters more than
minor sonic variations between microphones, the mileage of an inch of
movement of a pair used for an ensemble can be surprising if that inch of
movement takes your mic away from a "bad" reflection from the ceiling. Worry
less, record more, learn, enjoy!


I stumbled on an old issue (March 1995) of Video Toaster magazine
(unfortunately never having had the pleasure of owning an Amiga, let alone a
Video Toaster to go along with it), and Cliff Roth suggested on page 24 that,
in recording a four man band, you really ought to have four microphones just
for the drums, and probably a pair of microphones for every performer.
Placing four microphones by a drum necessarily involves different distances
from the drum. I suppose that would all be well and good, but another book I
have, says you should have microphones positioned on the sources of noise
(such as unwanted echoes, or maybe even traffic noise), just so you can
subtract them (one or more times) from the sound that you are actually trying
to record. I am not trying to digress. I understand what you mean by
carefully positioning your microphones in one place or another, and taking
pains to record separate tracks of the unwanted noise for no other purpose
than subtraction, but this is difficult for a person to reckon properly if his
hearing is already going.

And while I am on the subject of maintaining separate files of sound, are
there any programs that let you manipulate them with 128 bit integers (not
floating point).

When I scope around for software that will let me manage my sound files, these
files being raw files, you'd think they would realize that floating point
admits errors, just as 128 bit integer math does. But I have yet to see a
detailed discussion of what raw data really looks like (you know, in terms of
a hex dump).

I wasn't being facetious when I suggested the usefulness of sound
spectrographs. For people who are beginning to go deaf, this sort of thing
is essential to understand what we are dealing with. Not all sound
spectrographs are the same. They represent well-ordered collections of
"extracted frequencies" indexed by a time rate (milliseconds is pretty common,
I understand) and an intensity level such as volume.
  #10   Report Post  
Posted to rec.audio.tech
Richard Crowley Richard Crowley is offline
external usenet poster
 
Posts: 4,172
Default Condenser microphones and water?

Im_Beta_00 wrote:
Peter Larsen wrote:
Im_Beta_00 wrote:
Well, I am not yet deaf as a stone, but I think a sound
spectrograph would be better.


Surprise surprise, it can tell you how a microphone measures, but
not how it sounds


I think that's exactly what it /does/ measure.


Your sentiment is not shared by acknowledged experts, but
you are free to think what you wish.

I stumbled on an old issue (March 1995) of Video Toaster magazine
(unfortunately never having had the pleasure of owning an Amiga, let
alone a Video Toaster to go along with it), and Cliff Roth suggested
on page 24 that, in recording a four man band, you really ought to
have four microphones just for the drums, and probably a pair of
microphones for every performer. Placing four microphones by a drum
necessarily involves different distances from the drum.


I'm sure that Mr. Roth has brought some enlightment about audio
to the amateur videographers who read Video Toaster magazine.
Neither the author nor the magazine are noted as having any kind
of expertiese or authority on the art or technology of audio. There
are more different ways of micing a 4-man band (and even a drum
kit) than there are people on the planet.

I suppose
that would all be well and good, but another book I have, says you
should have microphones positioned on the sources of noise (such as
unwanted echoes, or maybe even traffic noise), just so you can
subtract them (one or more times) from the sound that you are
actually trying to record. I am not trying to digress. I understand
what you mean by carefully positioning your microphones in
one place or another, and taking pains to record separate tracks of
the unwanted noise for no other purpose than subtraction, but this is
difficult for a person to reckon properly if his hearing is already
going.


It would be nice if you could do that. But nobody has ever discovered
a successful method of applying it. Even people with extraordinary
hearing. If you find a way of doing that, the Hollywood studios alone
would pay millions of $$ for the process.

And while I am on the subject of maintaining separate files of sound,
are there any programs that let you manipulate them with 128 bit
integers (not floating point).


128 bits of dynamic range would destroy the universe as we know
it. Humans with perfect hearing can handle around 100dB of
dynamic range. 16-bits = 96 dB and is better than anything any
of us can hear in the real world.

When I scope around for software that will let me manage my
sound files, these files being raw files,


What does "manage" mean? What does "raw" mean? It is very
unlikely that you have "raw" files. But since you have revealed
nothing about where they came from or how you created them,
we can only guess that they are likely 16-bit linear uncompressed
files (like "wav", et. al.). Or maybe they are compressed files
like MP3, et.al.?

you'd think they would realize that floating point admits errors,
just as 128 bit integer math does.


Brownian motion of the air between the source and the mic,
along with the noise that one finds everywhere outside the
most pefect anechoic chamber introduce at least 10x more
"error" than even 32-bit floating point arithmetic. That is why
nobody bothers with any larger bit-depth for conventional
audio recording or processing.

But I have yet to see a detailed discussion of what raw data
really looks like (you know, in terms of a hex dump).


The format of audio files is well documented and easily available.
But first you must identify exactly what kind of files you have.

I wasn't being facetious when I suggested the usefulness of sound
spectrographs. For people who are beginning to go deaf, this sort
of thing is essential to understand what we are dealing with. Not
all sound spectrographs are the same. They represent well-ordered
collections of "extracted frequencies" indexed by a time rate
(milliseconds is pretty common, I understand) and an intensity level
such as volume.


The debate between measurement and perception has been raging
for decades. You are pretty late to that party. Good luck.




  #11   Report Post  
Posted to rec.audio.tech
Im_Beta_00[_2_] Im_Beta_00[_2_] is offline
external usenet poster
 
Posts: 5
Default Advice needed (was 'condensing water on microphones')

Richard Crowley wrote:
Im_Beta_00 wrote: I suppose
that would all be well and good, but another book I have, says you
should have microphones positioned on the sources of noise (such as
unwanted echoes, or maybe even traffic noise), just so you can
subtract them (one or more times) from the sound that you are
actually trying to record. I am not trying to digress. I understand
what you mean by carefully positioning your microphones in
one place or another, and taking pains to record separate tracks of
the unwanted noise for no other purpose than subtraction, but this is
difficult for a person to reckon properly if his hearing is already
going.


It would be nice if you could do that. But nobody has ever discovered
a successful method of applying it.


But they must have come close, or nobody would ever have bothered to write it
down in a book for me to stumble on?

Even people with extraordinary
hearing. If you find a way of doing that, the Hollywood studios alone
would pay millions of $$ for the process.


Wait!

Are you suggesting I shouldn't even try that?

As you can tell, I am a beginner. (Even you were a beginner once.)

I am going to shoot a digital film using the following setup:

Fostex FR-2LE (stereo recording mode turned on)
input #1 SGM-2X shotgun microphone on boom

input #2 R0de NTG-1 shotgun microphone
somewhat farther away, maybe a
good 10 feet away, in a cross
direction, mounted on a tripod
that is stationary.

Edirol R-09HR (an inexpensive stereo recorder)
input #3 SMX-10 directional stereo microphone
mounted on a tripod, about 20 to 30
feet away, pointed solely at the
expected source of noise, a street
that is usually empty, but you never
can tell.

Input #2 and Input #3 are pointed directly away from each other; they are in
a
straight line with the cast; if the 3rd file is subtracted from the 2nd file,
there ought to be an ordinary ambient background, i.e., a reference level, in
a
manner of speaking, against which to mix the sound recorded in the 1st file.

The sole purpose of the cheapie Edirol R-09HR is to pick up whatever street
noise there might be, for subtracting (possibly several times) from the
dialog. One problem, is that the Edirol R-09HR will be going continuously,
as it is not synchronized to the clap of the slate. We don't have the
luxory of shutting down the street, and I was hoping I could just pick up all
the crappy exterior noise as "back noise" for use as the mask to filter with,
later on.

I have additional recorders but no reel to reel recorders. And so far as I
can tell, the recorders I /am/ using, have no time codes stored in the course
of the recording process. So I am making do, with what I have at my
disposal.
  #12   Report Post  
Posted to rec.audio.tech
David Nebenzahl David Nebenzahl is offline
external usenet poster
 
Posts: 237
Default Advice needed (was 'condensing water on microphones')

On 10/10/2009 2:33 PM Im_Beta_00 spake thus:

I am going to shoot a digital film using the following setup:

Fostex FR-2LE (stereo recording mode turned on)
input #1 SGM-2X shotgun microphone on boom

input #2 R0de NTG-1 shotgun microphone

Edirol R-09HR (an inexpensive stereo recorder)
input #3 SMX-10 directional stereo microphone
mounted on a tripod, about 20 to 30
feet away, pointed solely at the
expected source of noise, a street


Well, it's plain enough to see what you're *trying* to do here,
especially with your second "noise-cancelling" recorder.

DISCLAIMER: IANARE (I am not a recording expert)

However, I can still tell you with confidence that it ain't gonna work.
Fuggedaboudit.

Since you're using 2 completely unsyncrhonized recorders, there's no way
in hell you're ever going to get that second recorder's sound to cancel
ambient noise picked up by the first recorder. Think about it a second
or three and I'm sure you'll agree. Being even a millisecond or so
within synch isn't close enough. And here you've got two recorders, one
an admittedly "cheap" one, and no time codes.

Noise cancelling is a whole 'nother can of worms altogether. Attempting
it on the cheap as you're proposing is futile.

The experts here can add lots more.


--
Found--the gene that causes belief in genetic determinism
  #13   Report Post  
Posted to rec.audio.tech
Richard Crowley Richard Crowley is offline
external usenet poster
 
Posts: 4,172
Default Advice needed (was 'condensing water on microphones')

Im_Beta_00 wrote:
Richard Crowley wrote:
Im_Beta_00 wrote: I suppose
that would all be well and good, but another book I have, says you
should have microphones positioned on the sources of noise (such as
unwanted echoes, or maybe even traffic noise), just so you can
subtract them (one or more times) from the sound that you are
actually trying to record. I am not trying to digress. I
understand what you mean by carefully positioning your microphones
in
one place or another, and taking pains to record separate tracks of
the unwanted noise for no other purpose than subtraction, but this
is difficult for a person to reckon properly if his hearing is
already going.


It would be nice if you could do that. But nobody has ever discovered
a successful method of applying it.


But they must have come close, or nobody would ever have bothered to
write it down in a book for me to stumble on?


Don't believe everything you read in a book.
The facts speak for themselves. And acoustic physics backs it up.

Even people with extraordinary
hearing. If you find a way of doing that, the Hollywood studios
alone would pay millions of $$ for the process.


Wait!
Are you suggesting I shouldn't even try that?


Knock yourself out. We won't expect any progress reports.

As you can tell, I am a beginner. (Even you were a beginner once.)


Perhaps you will learn something then.
Acoustical physics. Like gravity, its the law.
You'd have better luck inventing a perpetual motion machine.

Suggest enrolling yourself for college physics. Then at least
you will get some sort of credit for conducting the experiment.
OTOH, the professor probably won't allow it.


  #14   Report Post  
Posted to rec.audio.tech
Im_Beta_00[_2_] Im_Beta_00[_2_] is offline
external usenet poster
 
Posts: 5
Default Advice needed (was 'condensing water on microphones')

David Nebenzahl wrote:
On 10/10/2009 2:33 PM Im_Beta_00 spake thus:


snip

Since you're using 2 completely unsyncrhonized recorders, there's no way
in hell you're ever going to get that second recorder's sound to cancel
ambient noise picked up by the first recorder.


Firstly, whenever you are dealing with a recorder that has no time codes,
and I assume that none of the recorders listed have time codes, you are going
to find yourself doing some "hand-synchronizing" in post. I am not so nuts
that I would even *think* of mixing any of this stuff live. I need an
ambient background that serves as a "reference" level against which to mix
the foreground.

Secondly, this is an area roughly 3 acres in area. Just about every
direction from the shooting site is thick with trees (good for damping out
the really obnoxious stuff) except for that 80 foot driveway that comes from
the sporadically trafficked street road, where we expect the noise to be
coming from. That short little road is where the noise-cancelling recorder
is going to be. The cast is much farther away from the road.

The ambient noise of the wind, whatever it is, is going to be that much
worse, and potentially unsolvable, as we are going to be more or less at the
top of a mountain, even with windscreens on *all* of the mikes. It's not
like we are looking to record the sound of a proverbial pin dropping on the
floor. (And we are going to be mixing in some light background music to
prevent people from hearing the pin dropping on the floor, anyways.) So,
what we are actually concerned with, is the dialog of the cast, minus the
occasional car (50 or 60 feet away from the cast, maybe even 80 feet away)
zooming by.

Well, some of this depends on how "loud" the noise is. We won't be able
to cancel all of it, but some of it is bound to be useful.

Think about it a second
or three and I'm sure you'll agree. Being even a millisecond or so
within synch isn't close enough.


If I am within a millisecond, I am going to be doing a whole lot better than
if I were doing it a quarter second off. I expect to reduce the street noise
to a manageable sound level, maybe one fourth the sound level of the cast.
That means that not all of the noise can be subtracted out, but some of it
ought to be subtractable.
  #15   Report Post  
Posted to rec.audio.tech
Richard Crowley Richard Crowley is offline
external usenet poster
 
Posts: 4,172
Default Advice needed (was 'condensing water on microphones')

Im_Beta_00 wrote:
David Nebenzahl wrote:
On 10/10/2009 2:33 PM Im_Beta_00 spake thus:


snip

Since you're using 2 completely unsyncrhonized recorders, there's no
way in hell you're ever going to get that second recorder's sound to
cancel ambient noise picked up by the first recorder.


It wouldn't matter if you were recording on the SAME multi track
recorder. The laws of acoustics and physics deny any known solution
at this time.

Firstly, whenever you are dealing with a recorder that has no time
codes, and I assume that none of the recorders listed have time
codes, you are going to find yourself doing some "hand-synchronizing"
in post. I am not so nuts that I would even *think* of mixing any
of this stuff live. I need an ambient background that serves as a
"reference" level against which to mix the foreground.

Secondly, this is an area roughly 3 acres in area. Just about every
direction from the shooting site is thick with trees (good for
damping out the really obnoxious stuff) except for that 80 foot
driveway that comes from the sporadically trafficked street road,
where we expect the noise to be coming from. That short little road
is where the noise-cancelling recorder is going to be. The cast is
much farther away from the road.

The ambient noise of the wind, whatever it is, is going to be that
much worse, and potentially unsolvable, as we are going to be more or
less at the top of a mountain, even with windscreens on *all* of the
mikes. It's not like we are looking to record the sound of a
proverbial pin dropping on the floor. (And we are going to be mixing
in some light background music to prevent people from hearing the pin
dropping on the floor, anyways.) So, what we are actually concerned
with, is the dialog of the cast, minus the occasional car (50 or 60
feet away from the cast, maybe even 80 feet away) zooming by.

Well, some of this depends on how "loud" the noise is. We won't be
able
to cancel all of it, but some of it is bound to be useful.

Think about it a second
or three and I'm sure you'll agree. Being even a millisecond or so
within synch isn't close enough.


If I am within a millisecond, I am going to be doing a whole lot
better than if I were doing it a quarter second off.


It doesn't matter if you are time locked absolutely perfect to a
femtosecond. That isn't the issue. The issue is that the sound at
any two different points is guaranteed to be different, NOT JUST
IN TIME, and therefore cannot be cancelled by simple subtraction.
You are tilting at windmills. Once you have tried it and done a bit
more serious study of the underlying issues, you will realize that you
are playing a fools game.

I expect to
reduce the street noise to a manageable sound level, maybe one fourth
the sound level of the cast. That means that not all of the noise can
be subtracted out, but some of it ought to be subtractable.


Inpossible. You will never get there. People with budgets 10000000
times more than you have been unable to do this. And not for lack
of ideas or motivation. Actors who get paid millions and millions
of dollars for a single film still spend tedious hours and hours shut
up in ADR studios reproducing and re-recording their dialog in a
quiet studio environment. If there were some way of eliminating
this, do you REALLY think that someone wouldn't have discovered
this method by now?

Sorry to rain on your parade, but there are much more profitable
things that you could be spending your time and resources on.




  #16   Report Post  
Posted to rec.audio.tech
Im_Beta_00[_2_] Im_Beta_00[_2_] is offline
external usenet poster
 
Posts: 5
Default Advice needed (was 'condensing water on microphones')

Richard Crowley wrote:
Im_Beta_00 wrote:
Think about it a second
or three and I'm sure you'll agree. Being even a millisecond or so
within synch isn't close enough.


If I am within a millisecond, I am going to be doing a whole lot
better than if I were doing it a quarter second off.


It doesn't matter if you are time locked absolutely perfect to a
femtosecond.


Time-locking it is what ruins it. Sheeesh.

I suppose you are one of those people who can hear everything? I just want
to erase the roar of the car, or at worst, detect the moment of the roar,
and replace the relevant snip with a snip from a different microphone (one
that is not pointed in the direction of the roar.)

That isn't the issue. The issue is that the sound at any two different
points is guaranteed to be different,


Of course.

NOT JUST IN TIME,


I thought I just SAID that.

and therefore cannot be cancelled by simple subtraction.


It is not simple subtraction, and it isn't simple ANDing off the noise
and ending up with some miraculously "clean" track. If you thought that
was what I was getting at, I apologize.

You are tilting at windmills. Once you have tried it and done a bit
more serious study of the underlying issues, you will realize that you
are playing a fools game.


In terms of recording a few extra tracks (or "files"), redundancy always
helps. The more backup recorders I have, the better.
  #17   Report Post  
Posted to rec.audio.tech
Richard Crowley Richard Crowley is offline
external usenet poster
 
Posts: 4,172
Default Advice needed (was 'condensing water on microphones')

Im_Beta_00 wrote:
Richard Crowley wrote:
Im_Beta_00 wrote:
Think about it a second
or three and I'm sure you'll agree. Being even a millisecond or so
within synch isn't close enough.

If I am within a millisecond, I am going to be doing a whole lot
better than if I were doing it a quarter second off.


It doesn't matter if you are time locked absolutely perfect to a
femtosecond.


Time-locking it is what ruins it. Sheeesh.


No. Time-locking is IRELLEVANT.

I suppose you are one of those people who can hear everything?


No. And furthermore you have not made a case for how that
is relevant to anything??

I just want to erase the roar of the car,


You simply cannot remove wideband noise without doing
significant damage to the wideband signal of interest. Dunno
how many different ways we have to say this before you can
understand it?

or at worst, detect the
moment of the roar, and replace the relevant snip with a snip from a
different microphone (one that is not pointed in the direction of the
roar.)


Lot of work for absolutely nothing. But apparently you will
need to do the experiment for yourself since you refuse to
learn from the mistakes of others. Good luck.

If you have another mic picking up the signal of interest, but
without the noise, then why not just use that one and dump
the intrigue?

It is not simple subtraction, and it isn't simple ANDing off the noise
and ending up with some miraculously "clean" track. If you thought
that was what I was getting at, I apologize.


You have not mentioned any viable methodology of doing what
you say you want to do. If you have some new secret scheme
that you don't want to tell us about, then more power to you,
go for it. But none of the techniques you have mentioned here
are either new, unique, or proven effective.

In terms of recording a few extra tracks (or "files"), redundancy
always helps. The more backup recorders I have, the better.


Absolutely. No question that redundancy is always good just in
case something goes wrong. But it has nothing to do with noise
reduction.


Reply
Thread Tools
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
NEVATON.EUROPE - RUSSIAN CONDENSER MICROPHONES Nevaton Marketplace 0 August 4th 07 01:12 AM
Budget Condenser Microphones dazz Pro Audio 76 August 21st 05 01:30 PM
A question about dynamic and condenser microphones and maths TJ Hertz Pro Audio 19 July 3rd 05 08:38 PM
Radio Shack "Vintage" Condenser Microphones... Scott Dorsey Pro Audio 7 June 16th 05 03:12 PM
FS: AKG C-501E / C-502E Electret Condenser Microphones, 3 Extra Capsules Mark Glinsky Pro Audio 0 August 3rd 03 03:21 AM


All times are GMT +1. The time now is 07:16 PM.

Powered by: vBulletin
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 AudioBanter.com.
The comments are property of their posters.
 

About Us

"It's about Audio and hi-fi"